8.8

CVE-2026-3298: python software foundation cpython Out-of-bounds Write

CVSS: 8.8v4.0HighAwaiting analysis
AliasesUBUNTU-CVE-2026-3298CGA-2pf3-9r4v-7g9hCGA-5g3v-2wm4-prpw
Published 21-04-2026Last modified 13-08-2026
Open JSON

Vulnerability summary

CVE-2026-3298 is a high (CVSS 8.8) Out-of-bounds Write vulnerability in python software foundation cpython. EPSS estimates a 0.60% chance of exploitation in the next 30 days, higher than 48.1% of scored vulnerabilities.

Overall risk
35/100
0100
Medium · default modelHow is this calculated?
CVSS score
8.8/10
010
High · v4.0 (CVE.org)
EPSS score
0.60%
0%100%
Low · +0.21 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 0 · Related 1
CGA-252R-8VP6-7F2V

Timeline

  1. 21-04-2026
    PublishedVulnerability first disclosed.
  2. 13-08-2026
    Last modifiedVulnerability information updated.

Description

The method "sock_recvfrom_into()" of "asyncio.ProacterEventLoop" (Windows only) was missing a boundary check for the data buffer when using nbytes parameter. This allowed for an out-of-bounds buffer write if data was larger than the buffer size. Non-Windows platforms are not affected.

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.60%

Chance of exploitation in the next 30 days

Percentile

48%

Versus all other CVEs

30-day change

+0.21 pp

From 0.39% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.60%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Ubuntu12 products
  • python2.7All versions (No fix recorded)
  • python3.10All versions (No fix recorded)
  • python3.11All versions (No fix recorded)
  • python3.12All versions (No fix recorded)
  • python3.13All versions (No fix recorded)
Chainguard5 products
  • python-3.10All versions (No fix recorded)
  • python-3.11All versions (No fix recorded)
  • python-3.12All versions (No fix recorded)
  • python-3.13All versions (No fix recorded)
  • python-3.14All versions (No fix recorded)
Wolfi5 products
  • python-3.10All versions (No fix recorded)
  • python-3.11All versions (No fix recorded)
  • python-3.12All versions (No fix recorded)
  • python-3.13All versions (No fix recorded)
  • python-3.14All versions (No fix recorded)
Python software foundation1 product
  • cpython< 3.11.16 | ≥ 3.12.0, < 3.12.14 | ≥ 3.13.0, < 3.13.14 | ≥ 3.14.0a1, < 3.14.5rc1 | ≥ 3.15.0a1, < 3.15.0b1

4 vendors · 23 products

References

13 links
Show all 13 references